Stephanorhinus, Kretzoi, 1942
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publication ID |
https://doi.org/ 10.26879/985 |
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persistent identifier |
https://treatment.plazi.org/id/65303B38-FFBF-6760-FF46-6324FCCB4232 |
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treatment provided by |
Felipe |
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scientific name |
Stephanorhinus |
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Stephanorhinus hundsheimensis Toula, 1902
Holotype. Skeleton 2013/0282/0001 (Natural History Museum Vienna, Austria).
Type locality and horizon. Hundsheim (Lower Austria), early Middle Pleistocene ( MIS 15-13).
Occurrence. Latest Villafranchian and Galerian, late Early and early Middle Pleistocene of Europe (1.4–1.2 Ma until 0.6–0.5 Ma), and possibly Late Pleistocene of Western Asia (Caucasus).
Description.
Upper dentition: The specimen NMKVRS.P13 ( Figure 3 View FIGURE 3 A-E) is a left P3 or P4. Despite pronounced wear, this middle-large sized tooth is rather well-preserved, consisting of a complete crown (showing grey enamel and dark brown dentine) and partially preserved roots. The enamel surface is characterised by the presence of several dark vertical and subvertical lines (these lines may frequently be present but are not ubiquitous among Pleistocene rhinoceroses). The crown displays some rounding and polishing, indicating water transport as a taphonomic agent. The surface bears patches of black manganese coating and yellowish iron-oxide staining. In occlusal view, the crown is vestibulo-lingually wide and mesio-distally short, showing a rectangular outline. The occlusal surface is semi-smooth and polished showing the interior valley, the medifossetta, as well as the postfossetta. Mesially, the ectoloph curves quite drastically towards the interior of the tooth. No constriction of the protocone can be observed. An oblique lingual cingulum is present.
The fossil designated HMP-139b ( Figure 3 View FIGURE 3 F- H) is a right P3 or P4, consisting of a damaged dark brown crown with very pronounced rounding and polishing presumably by water transport. Large parts of the mesial, distal, and vestibular enamel are missing. The preserved occlusal surface shows marked wear, the presence of an interior valley, a single crochet, and the postfossetta. A partially preserved cingulum is present on the lingual and distal sides. The protocone seems to display a very slight constriction, although the pronounced wear makes this difficult to assess.
HMP-131 ( Figure 4 View FIGURE 4 A-E) is a rather well-preserved and complete crown of a large right molar (M1 or M2), with little wear, showing grey-yellow enamel, with extensive black manganese coating. The crown does not display much taphonomicallyinduced rounding or polishing. In occlusal view, the tooth is trapezoidal showing a well-marked ectoloph profile with a strong paracone fold, an open medisinus, a single crochet, and the postfossetta. Very shallow expressions of the antecrochet and crista can be observed; if the specimen showed more advanced wear, these features would have not been observed. The base of the protoloph appears rather bulbous (especially in lingual view); the protocone shows only a very slight constriction. In both the mesial and distal views the molar appears remarkably brachydont. The outlet of the interior valley displays a classic V-shape in lingual view. In vestibular view, the crown is slightly rough and shows some vertical and subvertical greyish lines. These lines may also be present in other portions of the crown, but they are not visible due to the manganese coating. Cingula are present on the bases of both the protocone and the hypocone, mesial and distal sides; the horizontal lingual cingulum continues as a prominent oblique mesial cingulum.
A right M1 or M2, specimen HMP-X ( Figure 4 View FIGURE 4 F-J) presents a rather complete but worn crown, with very little preserved of the roots; grey enamel is heavily yellow-stained (iron oxides), showing regions with manganese coating. The specimen displays only minimal taphonomic smoothing, confined mostly to the damaged roots. The occlusal view shows a trapezoidal-shaped crown typical for upper molars. Despite being obscured by the localised enamel damage, the presence of a paracone fold on the ectoloph profile is evident. A single crochet is present, and there is an open medisinus and a distinct postfossetta. The occlusal morphology does not include the presence of an antecrochet or crista. The protocone is markedly constricted. The cingulum can be observed on lingual, mesial, and distal (around the base of the metastyle) sides.
The specimen HMP-135 ( Figure 4 View FIGURE 4 K-O) is a left M1 or M2 consisting of a well-preserved and complete crown without roots, showing pronounced wear and grey-coloured, iron-oxide stained enamel. The crown shows rounded and polished surfaces (indicating water transport). A trapezoidal shape can be observed in occlusal view. The ectoloph profile displays a distinct, strong paracone fold. There is a relatively large single crochet, an open medisinus and the postfossetta. There is no antecrochet or crista. The base of the protoloph is rather bulbous, which is more evident in the lingual view; there is a strong constriction of the protocone. The outlet of the lingual valley shows an enlarged V-shape in lingual view. The enamel surface shows the presence of a large number of vertical and subvertical greyish-brownyellow lines. A small portion of a mesial cingulum can be seen under the protocone constriction, and also on the distal side (smoothed via taphonomic processes). The tooth appears rather brachydont.
The specimen HMP-136 ( Figure 5 View FIGURE 5 A-B) is a right M1 or M2, and it consists of a damaged crown, with vestibular part (ectoloph) and roots missing; the tooth has light brown colouration, different from other specimens reported in this paper. However, like some other specimens (HMP-131 and X), the mesial parts of the crown under the cingulum display black manganese staining. Despite damage, the trapezoidal crown outline is obvious. The wear is not pronounced, so many details of the occlusal morphology can be assessed. There is a rather strong crista and a large crochet; there is also a small second crista located between the crochet and the crista. The medisinus is open. Only a hint of an antecrochet can be observed. The postfossetta is marked. The protocone is only very lightly constricted and bulbously inflated. A horizontal cingulum is present on the lingual, distal, and mesial sides; the mesial cingulum presents a very prominent and sharp, continuous and oblique protuberance.
The fossil designated HMP-132 ( Figure 5 View FIGURE 5 C-D) represents only a vestibular right upper molar crown fragment with grey-coloured, smooth and polished enamel, showing several vertical and subvertical brown to yellow lines. The ectoloph profile bears a strong paracone fold. A part of the distal cingulum is preserved at the base of the metastyle.
The specimen HMP-134 ( Figure 5 View FIGURE 5 E-F) is a mesial half of the vestibular crown fragment of a larger right upper molar. The smooth and polished grey-coloured enamel displays many vertical and subvertical brown to yellow lines. A marked paracone fold is present.
The specimen HMP-130 ( Figure 5 View FIGURE 5 G-H) is a right upper deciduous tooth, probably a DP4. It consists of a very worn and damaged crown, with grey-bluish enamel with iron-oxide stains. The most damaged regions of the crown are the metacone and the hypocone; the roots are mostly missing, and only the lingual ones are preserved to some length. The crown shows a trapezoidal shape in occlusal view, with the distal side shorter than the medial one; the ectoloph profile is rather well marked (despite the damage to its mesial and distal portions), showing a strong paracone fold. The occlusal surface is smooth and polished (shiny), showing the lingual valley and the postfossetta, an open medisinus, and a single, quite massive crochet. The protocone, characterised by a pronounced constriction, appears remarkably bulbous. Unfortunately, the hypocone has been broken off. The enamel surface presents several vertical and subvertical brown lines. The cingulum can be seen on the preserved mesial side.
Lower dentition: The fossil designated HMP-129 ( Figure 6 View FIGURE 6 A-E) is a right m1 or m2, and it represents a perfectly preserved yellow-grey-coloured crown with mild wear, without roots. In occlusal view the crown shows a distinct paralophid and a well-defined mesial valley (i.e., trigonid basin); the mesial valley is narrower than the distal one, and both of them show a V-shape outline in lingual view. The opening of the vestibular syncline is right-angled. Oblique and continuous mesial and distal cingula are present (with interproximal wear), and they continue partially on the vestibular side.
A right p3 or p4 designated HMP-407 ( Figure 6 View FIGURE 6 F-J) preserves a complete worn crown and partial roots. The enamel is mostly yellow to brown, due to iron-oxide staining. This specimen does not show taphonomically induced rounding or polishing. It displays a relatively small mesial valley and a larger distal one, both with V-shaped outlines in the lingual view, and a right-angled vestibular syncline. Mesial and distal cingula (oblique and continuous) are evidently present, though obscured by interproximal wear; a faint, horizontal and discontinuous cingulum is present on the vestibular side of the crown as well.
A right p2 known as HMP-139a ( Figure 6 View FIGURE 6 K-O) represents a small-sized, yellow-grey crown in an excellent state of preservation, with only a mild degree of occlusal wear in its mesial portion; roots are missing. The crown displays a much reduced paralophid and metalophid, a well-developed hypolophid, a well-defined, lingually V-shaped, distal valley (i.e., talonid basin), a wide and right-angled opening of the vestibular syncline, and gracile mesial and distal cingula (the latter is reduced due to interproximal wear).
Metric Data
Dimensions for the well-preserved specimens are provided in Table 1. The comparative data (length and width ranges) are provided in Table 2. When regarded as P3, the specimen NMKVRS.P13 is within the reported ranges for Stephanorhinus etruscus , S. hundsheimensis, S. hemitoechus , and narrower and (only marginally) shorter than S. kirchbergensis P3. When regarded as P3, however, NMKVRS.P13 is smaller (shorter and narrower) than S. kirchbergensis P4, marginally shorter than S. hemitoechus P4 and marginally narrower than S. hundsheimensis P4. The upper molar HMP-X is shorter than S. kirchbergensis M1, while within the ranges for M1s of other taxa; HMPX is within the ranges for most of the M2 comparative taxa, albeit smaller than S. kirchbergensis M2 and below the width range reported for S. hemitoechus M2. The HMP-131 molar falls within the ranges for all the comparative taxa, both when viewed as M1 and M2, with a notable exception of being somewhat longer than S. etruscus M1. The HMP-135 upper molar fits the M1 and M2 data for three species ( S. etruscus , S. hundsheimensis, S. hemitoechus ), while being narrower than S. kirchbergensis M1, and smaller (in both dimensions) from S. kirchbergensis M2. The HMP-130 deciduous upper tooth is narrow relative to the (permanent) molars of all the comparative groups.
The HMP-139a lower second premolar is within the ranges of all taxa, except being marginally longer than Stephanorhinus hemitoechus p2. The specimen HMP-407 is within the ranges for most taxa both when viewed as p3 and p4; it only differs from S. kirchbergensis by being marginally narrower when viewed as M1, and by being narrower and marginally shorter when viewed as M2. Finally, the lower first or second molar HMP-129 is within the reported ranges for most groups, both when viewed as m1 and m2; however, this molar is narrower than S. kirchbergensis m1, and smaller (shorter and narrower) than S. kirchbergensis m2.
The Accompanying Mammalian Fauna
In addition to the rhinoceros material, dental remains of other Pleistocene large mammals were also collected from the site, including horse ( Equus sp. ) and an indeterminate bovid. These additional specimens display shiny, brown and black surfaces, which could indicate that the fossils originated from the same stratigraphic context as many rounded metaconid (Arceredillo, 2008). As seen in Figure 7A View FIGURE 7 , the specimen from Bogovina Cave clearly shows U-shaped entoflexid, thus indicating a caballoid horse. Furthermore, the size of molar (L = 33.8 mm, W = 14.7 mm; measured at the occlusal surface, excluding cement) is comparable to the large-sized group of caballoid horses of Forstén and Dimitrijević (2004), well-known from the caves and rock shelters of the Central Balkans. Indeterminate bovid ( Bovidae ) dental specimens were also discovered: a right permanent lower fourth premolar (p4) NMKVRS.P14 ( Figure 7B; L View FIGURE 7 = 25.3 mm, W = 16.8 mm) and a left upper molar (M1 or M2) NMKVRS.P15 ( Figure 7C; L View FIGURE 7 = 31.5 mm, W = 20.5 mm). We did not attempt to classify these two isolated specimens at genus and species levels, due to the well-known fact that large bovine teeth show great variability of proportions and structures ( Sher, 1997).
of the rhinoceros teeth (e.g., HMP-130, 139b). However, different stratigraphic provenance cannot be excluded.
The equid ( Equidae ) material consists of an isolated left lower molar (m1 or m2) NMKVRS.P12 ( Figure 7A View FIGURE 7 ). The genus Equus may be separated into two different lineages: the stenonid (zebroid) and the caballoid (true) horses. The most obvious dental differences between the two groups can be seen in the lower cheek teeth, namely, in the morphology of the metaconid-metastylid loops (the double knot) and in the shape of the entoflexids (i.e., linguaflexid sensu Skinner et al., 1972) ( Forstén, 1992). Stenonid lower premolars and molars are characterised by the V-shaped entoflexid, and concave protoconids and hypoconids; conversely, caballoids show U-shaped entoflexid with straight protoconids and hypoconids, and a
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